Lightning conductor

ABSTRACT

Lightning rods having around the rod at least one radioactive ionizing source comprising a chemically-inert gas such as Kr-85 whereby efficient lightning protection is insured and at the same time the danger present with solid radioactive material is eliminated.

, v United States Patent 51 3,662,083

Constant 1 May 9, 1972 54] LIGHTNING CONDUCTOR 3,328,508 6/1967 Ritter ..174/4 c 0,496 10 l 67 ..'l 4 [72] Inventor: Rene Constant, Mol-Donk, Belgium 3 35 9 Rmer 7 ,4 C [73] Assignee: Centre d'Etude de IEnergie Nucleaire en OTHER PUBLICATIONS abrege o Brussels Belgmm Lightning Rods Go Radioactive," Electrical World, January 22 Filed: Apr. 14, 1970 19, 4 1- [21] App]. No.: 28,423 Primary Examiner-William M. Shoop,.lr.

Attorney-Stevens, Davis, Miller & Mosher [30] Foreign Application Priority Data Apr. 15, I969 Belgium ..72,768 [57] ABSTRAU Lightning rods having around the rod at least one radioactive [if] ..l74/:():2,3i;;(6}(l) ionizing Source comprising a chemically inen gas Such as s i 4 Kr-85 whereby efficient lightning protection is insured and at a the same time the danger present with solid radioactive material is eliminated.

[56] Reerences i 14 Claims, 6 Drawing Figures UNITED STATES PATENTS 2,815,395 12/1957 Donelli ..174/4 C PATENTEUMY 91972 N 3,662,083

SHEET 1 OF 3 INVENTOR RENE CONSTANT M W W ATTORNEYS LIGHTNING CONDUCTOR This invention relates to a lightning conductor comprising a pointed rod and a radioactive source of [3 radiation which is supported by said rod adjacent the pointed end thereof.

The known lightning conductors of this kind do not release with certainly the required ionizing radiation and thus only give an insufficient protection against lightning. The source often also causes release of dangerous gamma rays. Said source may be highly toxic and the use thereof is consequently very dangerous. The danger is increased by the fact that the radioactive material is present as a solid which when the sheating surrounding the source is damaged, is still present as a more or less dense mass with dangerous radioactivity.

The invention has for object to obviate the drawbacks of said known lightning conductors and it relates to a lightning conductor which on the one hand insures the lightning protection and which on the other hand may be used far more safely than the present lightningconductors.

For this purpose, the radioactive source is a chemicallyinert gaseous source.

In a particular embodiment of the invention, said source is a source of Kr-85.

In an advantageous embodiment, said source has an activity in the range from 50 millicuries to curies.

In a preferred embodiment, the lightning conductor comprises at least two sources.

IN another embodiment, said source is located immediately adjacent to the rod.

Preferably the source is in direct electric contact with the rod.

In a very advantageous embodiment of the invention, the source is located inside a Faraday cage with large openings and in electric contact with the rod.

In a particular embodiment, the Faraday cage is formed by two collars of the rod and metal plates which connect said collars.

In a preferred embodiment, the plates are located in planes passing through the rod axis, the source extending between the collars in parallel relationship with said axis in the space bounded on the inside by the rod and on the outside by the plates.

In a further embodiment of the invention, the lightning conductor comprises a source adjacent each plate.

In still another embodiment of the invention, the number of the sources is equal to nine.

Other details and features of the invention will stand out from the description given below by way of non limitative example and with reference to the accompanying drawings, in which FIG. 1 is a perspective view of a lightning conductor according to the invention.

FIG. 2 is a view in section along a vertical plane passing through the axis of a second embodiment of a lightning conductor according to the invention.

FIG. 3 is a section view along line III-III in FIG. 2.

FIG. 4 is a view similar to FIG. 2 but showing only the central body of the lightning conductor, the section plane corresponding to line IV--IV in FIG. 5.

FIG. 5 is a section view along line V-V in FIG. 4.

FIG. 6 is a section view along line VI-VI in FIG. 4.

In the various figures, the same reference numerals pertain to similar elements.

The lightning conductor shown in F IG.- 1 comprises a rod 1 which is pointed at the upper end thereof and which is connected to earth. This rod comprises the lightning conductor proper.

Around said rod are mounted insulators 2 and 3 of cap shape, which retain between them a spherical element 4. The element 4 is made of metal. The unit formed by the insulator 2, the spherical element 4 and the insulator 3 is retained on the rod 1 between nuts 5 and 6 which are screwed on threaded portions of the rod 1. It is to be understood that in the insulators 2 and 3 is provided a hole for the passage of the rod 1 and that the spherical element is provided at the upper part and at the lower partthereof with holes surrounded by rims on which bear the insulators 2 and 3.

The spherical element 4 bears two arms 7 and 8 which extend radially. Said arms may extend along a direction at right angle to the rod 1, but they are preferably directed downwards with an angle of about 10 to the horizontal. Said arms are made of metal but they are insulated relative to the rod 1, as the spherical element which bears the arms 7 and 8 engages the rod 1 but through the insulators-2 and 3. The ends 9 and 10 of the arms 7 and 8which are remote from the rod I are pointed. Said ends are located adjacent a ring 11 which is connected by bent bars 12 and 13 t0 the lower insulator 3.The ring 11 is concentric with the rod 1 and it lies in a plane at right angle thereto. As the ring 11 does engage the rod only through the unit comprised of the bent bars 12 and 13 and of the insulator 3, it is insulated relative to said rod.

Inside the arms 7 and 8 are mounted the radioactive sources 14 and 15 which have a total radioactivity in the range from i 50 millicuries to 5 curies.

The sources 14 and 15 are gaseous sources which are chemically inert and release [3 rays. They are preferably comprised of Krinside a brass container with nickel window having a thickness of about 0.02 to 0.08 mm. The container has for example a length of 195 mm and a width and height of 29 mm. The dimensions of the window are for example 135 .x 15 mm.

Said sources provide with complete certainty the required ionizing radiation. The efficiency of the lightning conductor, that is the fictitious height of the apparatus is thus substantially increased with respect to the present lightning conductors. The safety of use of the lightning conductor according to the invention is' also increased relative .to present lightning conductors. Indeed krypton is a rare gas which may not be fixed biologically in human tissues. It belongs to the species of the radio-elements with low toxicity and it brings no problems as regards to contaminating, notably due to the fact that it is a gaseous material which is chemically inert. If the container is damaged, the gas dissolves in the air.

The lightning conductor shown in FIGS. 2 to 6 comprises a main body 101 the lower part 102 of which is threaded and is to be screwed in the upper part of a pole (not shown). The upper part 103 of said main body 101 is also threaded on said upper part 103 is screwed the point 108.

The point 108, the main body 101 and the pole (not shown) comprise together the lightning conductor rod in such a way that the main body may be considered as a portion of the rod.

The main body 101 is provided between the upper part thereof 103 and the center part with a collar 104 said body 101 is also provided with a collar 105 between the lower part 102 and the center part.

In the upper collar 104 are provided nine channels 106. Said channels have a constant diameter over the whole height thereof. In the lower collar 105 are also provided nine channels 107. The channels 106 and 107 are coaxial above each channel 107 thus lies a channel 106. The channels 107 have in the upper part thereof a diameter which is approximately equal to the diameter of the channels 106 the channels 107 have a larger diameter in the lower part 117 thereof.

The channels 107 are closed by plugging parts 115 the head i 116 of which is received in the lower part 117 of said channels.

The radioactive sources release B rays. They are preferably comprised of Kr-85 sources; they are nine in number, said number corresponding to the number of channels 106 and of channels 107. Each source is provided with an enclosure 111 for the gas which is bounded by a sleeve 110, an upper plug 112 and a lower plug] 13.

The sleeve which comprises the enclosure for the gas is made for instance of nickel and it has a thickness of about 25 p. The upper plug 112 and the lower plug 113 are for example 1 made of stainless steel. The upper plug 113 comprises a small filling tube 114 which projects outwards and which is closed on the same side.

On the source side the plugging part .115 has a recess for receiving the projecting part of the filling tube 114. A spring 118 bears on the one hand on the source upper plug 112 and on the other hand, on the lower surface of a washer 109 which is present between the upper surface of the collar 104 and the lower surface of the point 108.

Adjacent the channels 106 and 107, small plates 119 are soldered to the collars 104 and 105. Said plates 119 extend in planes that pass through the rod axis, that is the axis of the main body 101 and the point 108. The plane of each plate 119 also passes through the axis of a channel 106 and of a channel 107. Each plate is soldered against the cylindrical wall of the collar 104 and to the upper fiat surface of the collar 105.

Thecollars 104 and 105 and the small plates 119 form a Farady cage which has however large openings due to the spacing of the plates 119. Said Faraday cage with large openings is however sufficient to protect the sources it does comprise against direct discharges.

The main body 101, the point 108 and the small plates 119 are made of metal. The sources are thus in direct electric contact by the plug 112 thereof, the springs 118 and the washer 109 with the rod of the lightning conductor to which belong the main body 101 and the point 108.

There results from the above that the sources are located immediately adjacent to the rod, they are in electric contact therewith and they lie somewhat below the pointed end of the rod.

The sources are easy to mount indeed before assembling the washer 109 and the point 108, said sources may be slipped through the channels 106 up to the point where the lower plug 113 of said sources engages the plugging part 115 received in the collar 105. To prevent any damage to the projecting part of the small tube 114 when it is introduced in the corresponding recess of the plugging part 115, said part is made of some less hard material, such as a plastic material. Before mounting the washer 109 and the point 108 on the main body 101, springs 118 are introduced inside the channels 106 above the source plugs 112.

It is to be noted that the mounting of the sources in direct contact with the rod is made possible by the fact that a volatilizing of one or a number of sources would not cause any danger because the krypton which is a rare gas, would dilute immediately and could not become contaminating in any way.

Indeed it cannot form some chemical compound and thus it cannot be fixed to any body.

Because the sources release B rays, that is a penetrating radiation, the sleeve may be relatively thick and at the same time a sufficient radiation is insured through a water film which forms on the sleeve due to the rain which usually comes with the thunder-storms.

It must be understood that the invention is in no way limited to the above embodiments ant that many changes may be brought therein without departing from the scope of the invention as defined by the appended claims.

For instance, the number of sources per lightning conductor may vary within large limits.

I claim:

1. Lightning conductor comprising a pointed rod and a radioactive source of B radiation which is supported by said rod adjacent the pointed end thereof, in which the radioactive source is a chemically-inert gaseous source.

2. Lightning conductor as claimed in claim 1, in which said source is a source of Kr-85.

3. Lightning conductor as claimed in claim 1, in which said source has an activity in the range from 50 millicuries to 5 cums.

4. Lightning conductor as claimed in claim 1, which comcentric therewith, said ring being insulated relative to said rod. 7. Lightning conductor as claimed in claim 1, in which said source is located immediately adjacent to the rod.

8. Lightning conductor as claimed in claim 7, in which the source is in direct electric contact with the rod.

9. Lightning conductor as claimed in claim 1, in which said source is located somewhat below the pointed end of the rod.

10. Lightning conductor as claimed in claim 1, in which the source is located inside a Faraday cage with large openings and in electric contact with the rod.

11. Lightning conductor as claimed in claim 10, in which the Faraday cage is formed by two collars of the rod and metal plates which connect said collars.

12. Lightning conductor as claimed in claim 11, in which the plates are located in planes passing through the rod axis, the source extending between the collars in parallel relationship with said axis in the space bounded on the inside'by the rod and on the outside by the plates.

13. Lightning conductor as claimed in claim 11, which comprises a source adjacent each plate.

14. Lightning conductor as claimed in claim 13, in which the number of the sources is equal to nine.

UNITED STATES PATENT OFFICE CERTIFICATE OI CORRECTION Dated Patent No. 3,662,083

Inventor(s) Rene Constant It ."is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Line [30] .-March 3]., 1970, Belgium .87, 154-- Signed and sealed this 6th day of August 197A.

(SEAL) Attest:

MCCOY M, GIBSON JR. C. MARSHALL DANN I Attesting Officer Commissioner of Patents May 9, 1972 UNITED STATES PATENT OFFICE CERTl.FICA'I-E OF CORRECTION Patent No. 3 662 O83 Dated May 9 1972 Invent0r(s) Rene Constant It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Line [30] March 31, 1970, Belgium ..87,l54"' Signed and sealed this 6th day of August 1971+.

(SEAL) Attest:

MCCOY M. GIBSON, JR. 7 c. MARSHALL DANN Commissioner of Patents Attesting Officer 

2. Lightning conductor as claimed in claim 1, in which said source is a source of Kr-85.
 3. Lightning conductor as claimed in claim 1, in which said source has an activity in the range from 50 millicuries to 5 curies.
 4. Lightning conductor as claimed in claim 1, which comprises at least two sources.
 5. Lightning conductor as claimed in claim 4, in which said sources are incorporated into arms which are insulated with respect to the rod.
 6. Lightning conductor as claimed in claim 5, in which those arm ends which are remote from the rod lie adjacent a ring which is located in a plane at right angle to the rod and concentric therewith, said ring being insulated relative to said rod.
 7. Lightning conductor as claimed in claim 1, in which said source is located immediately adjacent to the rod.
 8. Lightning conductor as claimed in claim 7, in which the source is in direct electric contact with the rod.
 9. Lightning conductor as claimed in claim 1, in which said source is located somewhat below the pointed end of the rod.
 10. Lightning conductor as claimed in claim 1, in which the source is located inside a Faraday cage with large openings and in electric contact with the rod.
 11. Lightning conductor as claimed in claim 10, in which the Faraday cage is formed by two collars of the rod and metal plates which connect said collars.
 12. Lightning conductor as claimed in claim 11, in which the plates are located in planes passing through the rod axis, the source extending between the collars in parallel relationship with said axis in the space bounded on the inside by the rod and on the outside by the plates.
 13. Lightning conductor as claimed in claim 11, which comprises a source adjacent each plate.
 14. Lightning conductor as claimed in claim 13, in which the number of the sources is equal to nine. 